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Mental Nerve

nervus mentalis

The mental nerve is the terminal sensory branch of the inferior alveolar nerve, exiting through the mental foramen on the lateral mandible to supply lower lip and chin sensation. It is the nerve producing the lower lip numbness that patients experience after inferior alveolar nerve blocks for lower dental procedures — the mental nerve block itself is used for chin and lower lip analgesia in facial lacerations and chin implant surgery.

Region: Head & Skull

Anatomical Data

Origin, Insertion & Supply

Origin	Inferior alveolar nerve (V3) terminal branch

Clinical Relevance

Clinical Notes

The mental nerve is at risk in mandibular body fractures through or near the mental foramen, in implant placement adjacent to the foramen, and in chin augmentation surgery where the nerve must be identified and protected. Persistent lower lip numbness after chin surgery or mandibular procedures usually resolves but may indicate permanent nerve damage if the nerve was transected.

Pathology

Common Injuries & Conditions

Mental Nerve Injury

Lower lip and chin numbness from mental foramen fracture, implant encroachment, or surgical transection during chin procedures, usually temporary but potentially permanent.